spi: Provide multiple annotation types.

spi: Provide multiple annotation types.

For now SPI gets the following annotation types:

 - MISO/MOSI SPI data
 - MISO SPI data
 - MOSI SPI data

(i.e. you can see either MISO, or MOSI, or both; the latter is most
useful for CLI usage)

Also, show the hex values as e.g. F5 (upper-case letters, no "0x" prefix).